Hidden posts

It is that I want to also use topics or posts as static pages to link them from the navigation bar (about, norms of use…). For that reason it does not interest to me that the static page leave related like a post, nor to place them like sticky post.

You could always create a plugin which “hides” certain posts from the forum front-page/forum pages. I don’t think there’s anything available that does that now… the closest I’ve seen is this bb-Pages plugin:

I already know that plugin. In fact I found the operative version of the same and I proved it. It has some deficiencies that I did not like. I rejected to use it. I do not understand the reason bbPress does not include the use of static pages. He is not so complicated. On the other hand, I prefer not to use plugins, if I can avoid it. For that reason I prefer to find another form through some function that I can incorporate to the code of my template.